Skip car hoist winch mechanism

ABSTRACT

Described is a novel winch drive mechanism for skip cars and the like utilized to charge materials into a blast furnace, the mechanism being characterized in that the cable drive for the cars incorporates movable sheaves which permit an empty skip car at the top of the skip bridge to become righted and start its descent down a skip bridge before any substantial pulling force is imparted to the loaded skip car at the bottom of the skip bridge. In this manner, the weight and momentum of the descending skip car reduces the torque required to accelerate the car and its load at the bottom of the skip bridge, thereby reducing the torque requirements of the drive motors and minimizing stresses in the drive mechanism.

United I States Patent I William A. Munson lnventor l Williamsville, N.Y.

Appl. No 816,589

Filed Apr. 16, 1969 Patented Jan. 19, 1971 Assignee Westinghouse Electric Corporation Pittsburgh, Pa.

a corporation of Pennsylvania SKIP CAR HOIST WINCH MECHANISM [56] References Cited UNITED STATES PATENTS 868,639 10/1907 Brown 214/19 2,401,150 5/1946 Guy 214/19 Primary Examiner-Robert G. Sheridan AttorneysF. H. Henson, R. G. Brodahl and M. F. Oglo ABSTRACT: Described is a novel winch drive mechanism for skip cars and the like utilized to charge materials into a blast furnace, the mechanism being characterized in that the cable drive for the cars incorporates movable sheaves which permit an empty skip car at the top of the skip bridge to become righted and start its descent down a skip bridge before any substantial pulling force is imparted to the loaded skip car at the bottom of the skip bridge. in this manner, the weight and momentum of the descending skip car reduces the torque required to accelerate the car and its load at the bottom of the skip bridge, thereby reducing the torque requirements of the drive motors and minimizing stresses in the drive mechanism.

PATENTEUJANIQISYI $556,321

FIG.|.

H 4 0 INVENTOR William A. Munson ATTORNEY sxrr can no sr wmcu MECHANISM BACKGROUND or rHEiNvENTioir While not limited thereto, the present invention is particularly adapted for use in' a blast furnace skip car system. As is known, iron ore, coke and limestone are-charged into the top of a blast furnace by means of a pair of skip cars which run on adjacent'inclinedtrackstusually called a skip bridge leading from ground level'to'the topof the furnace. These skip ca'rs are inte'rconnected'by means ofacabl'e and winch system such that as one filled car. ascends the tracks, the other empty car descends.

As a tilled car starts. its ascent, a very large torque is required to accelerate it to the desired speed: This is due not only to the inherent weight of the skip car and the friction of the system, but is'also ducto the fact that the skip bridge track is curved to a steep vertical angle in thelower pit" or loading two cars counterbalance each otheri and it is necessary only to provide the required accelerating torque'to, overcome the inertia of the complete'system as well as the accelerating torque for the load in the filledskip car and other system friction losses, v

' In prior artskip car systems-the empty skip car does i not counterbalancethe lower filled car when it is initially ac celerated. Thisis due tot-the fact that'the upper ends .Of th O ward wheel skip bridge tracks are curved downwardly, I wherebythe gear may be inclined. downwardly to discharge its contents into a blast furnace receiving hopper.- In its'inclined or inverted'position for discharge, the empty skip {car exerts little or no counterbalancing torque on the system; and in prior art systems, this counterbalancingtorque was not fully applied until the empty car was rightedand started down the skip tracks; However, this was after the inertia of the filled car at the bottom of the track had already been overcome. As will be understood, this lackof a counterbalancing weight during initial acceleration of theloaded car materiallyincreases the initial torque requirements of the drive motors for the system.

For that matter, the basic skip car-weight is usuallyequal to 7 about half that of the maximum load, meaning-that the equiptravel from loading positions at the bottom of each track to the cable-24 passes around sheaves 36'and 38 and thence to ment sizing'ha's to be such that the initial torque requirements are increased over that needed to handle the basic counterbalanced load'by approximately SQpercent.

BRIEF SUMMARY or THE INVENTION its inverted discharge position and counterbalances the weight of the other car. In this manner, the initial torque required to 1 accelerate the loaded skip car is materially reduced.-

More specifically, an object of the invention is to provide a skip car drive mechanism of the type described wherein weighted, movable sheave devices areinterposed between a' winch drum and theskip cars to enable. an empty car to come to rest at the bottom of a skip bridge before a loaded car at the top of the skip bridge empties its contents. During the movement of the upper car while the lower car-is at rest, cable slack discharge-positions at the top of each track where the cars are inverted to discharge their contents into the furnace. The skip cars are interconnected by means of cables, portions of which are wound about a rotatable winch drum whereby rotation of the winch drum will cause one of the skip cars to ascend the track while the other descends, and vice versa. In order that i the weight of the descending car will counterbalance that of the loaded car at the bottom of the winch drum before pulling torque-is applied to the loaded car, means including at least one movable sheave device is interposed between the winch drum and a skip car for preventing'the pulling torque from being applied to a loaded skip car at thebottom of its track until the empty skip car has been moved from its inverted "discharging position to a position where it has started to descend its track. 7 q

The aboveand other objects andfeatures of the invention will become apparent from the following detailed description takenin connection with theaccompanying drawings'which I form a part of this specification, and in which:

1 FIG. 1 is a perspective view showing'the general overall arrangement of a skip car loading system for a blast furnace installation; and a FIG. 2 is a detailed schematic diagram of one embodiment Y of the invention.

With reference now to the drawingsand particularly to FIGS. 1 and 2,- the reference numeral- 10 dejsignatesthe receiving hopper of a blast furnace,'schematically illustrated at 12.

Extending upwardly from ground level to the top of the blast furnace 12 is a skip bridge 14 comprising apair of side-by-side tracks 16 and 18 (FIG. 1) on. whichjskip cars-20 and 22,

respectively, move. The two skip cars-20 and 22 are intercorinect'ed by means of cables 24 and ZSwhich extend from skip car 20 around sheaves 26 and 28 and thence to a winchdrum 30 (FIG. 2) around which it is wound a number of times. The winch drum and its associated drive motor 32, shown in FIG.

2, are normally housed within a hoist'house 34 adjacent to the blast furnace 12 as shown in FIG. I. From the winch drum 30,

20 will be caused'to move up its track 16 while the skip car 22 is permitted to move downwardly on the adjacent track 18. At the bottom of the skip bridge 14, materials to be charged into the blast furnace are fed into skip car 22, for example, from a chute 40. When either one of the skip cars reaches the top of the skip bridge 14, its rear wheels are caused to move along track section 42 (FIG. 2) and its forward wheels along downwardly curved track section 44, thereby tipping the skip car to discharge its contents into the receiving hopper 10 of the blast furnace 12.

When the skip cars 20 and 22 are traveling along the main portion of the tracks 16 and 18, the weight of car 20 will counterbalance that of car 22, the pull or torque on the winch drum 30 following acceleration conditions being primarily that due to the load within the loaded car 22 as well as the friction and is taken up by means of the aforesaid weighted, movable 7 sheave device which, when the mechanism is reversed, pays out the cable slack until the cable for the loaded skip car is again taut; whereupon pulling torque is applied to the loaded skip car. By this time, however, the empty skip car has started inertia of the system. However, when the upper skip car 20 as shown in FIG. 2, for example, is in its inverted discharging position, it exerts essentially little or no downward pulling force on the cable 25. As a result, in prior art skip hoist.

mechanisms, little or no counterbalancing effect by the upper skip car was transmitted to the lower, loaded skip car when it was initially accelerated from zero speed. The problem was further complicated by the fact that the lower portions of the tracks 16 and 18 are curved into a steep vertical angle in order to position the lower skip car in an upright position to facilitate loading.

In accordance with the present invention, the problem of high initial torque on the drive motors to accelerate the lower, loaded skip car is alleviated by the use of'a pair of movable sheave devices, generally indicated in FIG. 2 by the reference numerals 46 and 48. The movable sheave device 46 is provided for the skip car 22 and includes a movable sheave 50 which can reciprocate along guideways or tracks 52 from the rearward solid line position shown to the forward dotted line position, and vice versa. The movable sheave 50, in turn, is connected by a cable 54, which passes around sheave 56, to a weight 60 which tends to pull the sheave 50 to the left as viewed in FIG. 2. The cable 24, after passing around sheave 36, then passes around sheave 62, then sheave 50 and finally sheave 64. in this manner, it will be appreciated that any slack in the cable 24 between skip car 22 and winch drum 30 will be absorbed by movement of the sheave 50 to the left under the influence of weight 60.

In a similar manner, a movable sheave device 48 for skip car includes a movable sheave 66 reciprocable along guideways or tracks 68 from the forward full line position shown to a rearward dotted line position. The sheave 66, like sheave 50, is connected through a cable 70, which passes around sheave 72, to a weight 74. The cable 25, after passing around sheave 28 passes around sheave 76, thence the movable sheave 66 and finally around sheave 78 to the winch drum 30.

When both of the skip cars 20 and 22 are traveling along the main, straight sections of the tracks 16 and 18, substantial tension will be experienced in the cable section between car 20 and winch drum as well as the cable section 24 between car 22 and drum 30. However, the system is such that the skip car 22, for example, at the lower end of the skip bridge 14 engages stops 80 before the upper skip car 20 has been pulled into its inclined, discharging position shown in FIG. 2. As a result, while torque continues to be applied to the cable section 25 connected to the skip car 20, no downward pulling force is exerted on the cable section 24 connected to car 22; and the slack is taken up by movement of the sheave 50 to the left under the influence of weight 60. This is the position of the sheave devices 46 and 48 shown in FIG. 2.

Now, when the winch drum 30 is reversed, the weight of the upper skip car 20 will cause it to right itself by movement of its back wheels along the track section 42. Torque is also applied to the cable section 24 connected to car 22', but this torque is utilized at this time to pull the movable sheave 50 to the right and into the dotted line position shown against the force of weight 60. When the sheave 50 reaches its dotted line position, the upper, empty car will have righted itself and will be exerting a downward pull on the cable connected thereto, thereby counterbalancing the empty weight of the lower car 22. Now, when the car 22 is initially accelerated, it is assisted by the downward pull of the upper, empty car 20. As car 20 continues to move downwardly and car 22 moves upwardly, both of the movable sheaves 50 and 66 will be pulled forwardly. However, when car 20 reaches the bottom of the skip bridge 14 and engages the stop 80, a slack condition will be produced in the cable 25 connected thereto, causing the weight 74 to move the sheave 66 to the right and into the dotted line position shown in FIG. 2. Now, the loaded car 22 is moved into an inverted discharging position. Reversal of the winch drum 30 will then right the emptied car while the sheave 66 moves to the left until a pulling torque is again applied to the lower skip car, which is now car 20.

It can thus be seen that the present invention provides a means whereby the required acceleration torque on a skip car drive system is materially reduced by virtue of the fact that torque is not applied to the lower skip car until the upper skip car is exerting a downward pull on the cable means interconnecting the two cars.

Although the invention has been shown in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that vario'bs changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim:

1. in blast furnace charging apparatus, a pair of skip cars, a pair of inclined tracks leading into the top of the furnace and on which the respective skip cars travel from loading ositions at the bottom of each track to discharge positions at t e top of each track where the cars are inverted to discharge their contents into the furnace, apparatus including cable means interconnecting said skip cars, said apparatus also including a rotatable winch drum means around which said cable means is wound whereby rotation of the winch drum will cause one of said skip cars to ascend its track while the other descends, and means including at least one movable sheave device interposed between the winch drum means and a skip car for preventing pulling torque from being applied to a loaded skip car at the bottom of its track until the empty skip car has been moved from its inverted discharge position to a position where it has started to descend its track, whereby the weight of the empty descending skip car exerts a pulling torque on said cable means before said lower, loaded skip car is accelerated from rest.

2. The charging apparatus of claim 1 wherein there are two movable sheave devices, one of said movable sheave devices being interposed between said winch drum means and a first of said skip cars and the other of said movable sheave devices being interposed between the winch drum means and a second of said skip cars.

3. The charging apparatus of claim 1 wherein said cable means passes around a first sheave, thence around said movable sheave device, and then around a second sheave device whereby movement of the movable sheave device away from said first and second sheaves produces a loop in said cable means at right angles to the normal path of travel of the cable means.

4. The charging apparatus of claim 3 including a weight connected to said movable sheave for normally urging it away from said first and second sheaves.

5. The charging apparatus of claim 1 including stops at the bottoms of said tracks for stopping a lower skip car before an upper skip car has been completely inverted into its discharge position. 

1. In blast furnace charging apparatus, a pair of skip cars, a pair of inclined tracks leading into the top of the furnace and on which the respective skip cars travel from loading positions at the bottom of each track to discharge positions at the top of each track where the cars are inverted to discharge their contents into the furnace, apparatus including cable means interconnecting said skip cars, said apparatus also including a rotatable winch drum means around which said cable means is wound whereby rotation of the winch drum will cause one of said skip cars to ascend its track while the other descends, and means including at least one movable sheave device interposed between the winch drum means and a skip car for preventing pulling torque from being applied to a loaded skip car at the bottom of its track until the empty skip car has been moved from its inverted discharge position to a position where it has started to descend its track, whereby the weight of the empty descending skip car exerts a pulling torque on said cable means before said lower, loaded skip car is accelerated from rest.
 2. The charging apparatus of claim 1 wherein there are two movable sheave devices, one of said movable sheave devices being interposed between said winch drum means and a first of said skip cars and the other of said movable sheave devices being interposed between the winch drum means and a second of said skip cars.
 3. The charging apparatus of claim 1 wherein said cable means passes around a first sheave, thence around said movable sheave device, and then around a second sheave device whereby movement of the movable sheave device away from said first and second sheaves produces a loop in said cable means at right angles to the normal path of travel of the cable means.
 4. The charging apparatus of claim 3 including a weight connected to said movable sheave for normally urging it away from said first and second sheaves.
 5. The charging apparatus of claim 1 including stops at the bottoms of said tracks for stopping a lower skip car before an upper skip car has been completely inverted into its discharge position. 